Impact of toll-like receptor 4 variations on nasopharyngeal carcinoma risk and survival in tunisian population.

INTRODUCTION: The Toll-like receptor 4 (TLR4), an important member of the host's innate immune response, is coded by a polymorphic gene. This polymorphism could be a predisposing factor for NasoPharyngeal Carcinoma (NPC). AIM: To determine the association between TLR4 gene polymorphisms and the susceptibility to NPC in a cohort of Tunisian affected patients. METHODS: Genomic DNAs from 245 unrelated patients affected by undifferentiated carcinoma type (UCNT) and 264 unrelated healthy controls were genotyped for the five single nucleotides polymorphisms (SNPs) of TLR4 locus (4434 A>G (rs1927914),7263 G>C (rs10759932), 6134 A>G(rs4986790), 8851C>T (rs 4986791), 5272 T>C(rs11536889), +8469 T>C (rs11536891)) by Taqman® 5'-nuclease assay. RESULTS: Among all polymorphisms studied, only the rs4986790 G and rs4986791 T alleles were significantly more prevalent in patients' group than controls (45% vs. 38%; p=0.03; pc=0.06) and increased the risk of the NPC (OR=1.3, 95% CI=1.01-1.69). Also, we found that the frequency of the rs4986790 AA and rs4986791 TT genotypes was significantly higher in controls than in patients (25.7% vs 37%; p=0.006, pc=0.02) and conferred a protector factor in NPC (OR= 0.59, 95% CI= 0.39-0.87). Further, based on the Kaplan-Meier survival curve we observed also the positive effect ofrs1927914 AA genotype on a prognostic of NPC (p=0.006; pc=0.01). CONCLUSION: Our study demonstrated that impaired production of TLR4 seems to be a risk factor of NPC development but functional studies are needed to confirm these findings. As to rs1927914 AA appears to be a good biomarker for better survival in a patient with NPC.

MDM2 344T>A polymorphism; could it be a predictive marker of anthracycline resistance?

PURPOSE: To find a possible association between the Mouse Double Minute 2(MDM2) 344T>A, alone and in combination with p53 72 Arg/Pro polymorphism, and resistance to anthracycline-based chemotherapy of breast cancer in Tunisia. METHODS: This study enrolled 542 patients with invasive ductal carcinoma (IDC) treated with anthracycline-based chemotherapy. Genomic DNA was isolated from whole blood, using the phenol chloroform method. Anthracycline response was scored according to the World Health Organization (WHO). MDM2 344T>A polymorphism was genotyped using real time polymerase chain reaction (RT-PCR) with the TaqMan method. Data was statistically analyzed using the x2 test. RESULTS: Response was evaluated in 400 patients, of whom a quarter was found to be resistant to chemotherapy. Genetic data revealed that resistance to anthracycline-based chemotherapy did not seem to be correlated with 344T>A polymorphism in the studied population. Also, no significant association was found between the single nucleotide polymorphism (SNP) 344T>A status and clinicopathologic parameters (p>0.05 for all comparisons). Moreover, analysis of p53 rs1042522 and MDM2 rs1196333 combination showed no significant association between these two genetic variants and anthracycline resistance (p=0.2). CONCLUSIONS: Our findings provide no evidence indicating that SNP 344 T>A may affect response to anthracycline-based chemotherapy. However, the results obtained from the combination of SNPs 344T>A of MDM2 and 72 Arg/Pro of p53, do not support the hypothesis of the prominent role of common p53 and MDM2 variations in the genetic mechanisms of chemotherapy resistance in breast cancer.

Role of p53 Codon72 SNP in breast cancer risk and anthracycline resistance.

BACKGROUND/AIM: We undertook a case-control and a case-case study to examine the possible association of p53 codon72 polymorphism with the breast cancer risk and resistance to anthracycline-based chemotherapy. PATIENTS AND METHODS: Case-control study: This study enrolled 175 patients with breast cancer treated at the Salah Aziez Institute and 159 healthy Tunisian women (matched for age, ethnicity and origin), used as a control, with no clinical evidence of any neoplastic disorder. Case-Case study: 400 breast cancer patients, with invasive ductal carcinoma (IDC) treated with anthracycline based-chemotherapy. Genomic DNA was isolated from whole-blood leucocytes using the phenol-chloroform method. Anthracycline response was scored according to the World Health Organization (WHO) criteria. P53 codon72 polymorphism was genotyped using real-time polymerase chain reaction (RT-PCR) with the TaqMan method. Data were statistically analyzed using the Chi-square test. RESULTS: Clinical data revealed that among the 400 patients, one quarter was resistant to chemotherapy treatment. Genetic data revealed that the p53 Arg72Pro genotype was found to be greatly associated with breast cancer risk (p<0.001), as well as tumor site (p=0.046). However, resistance to anthracycline-based chemotherapy does not seem to be correlated with p53 codon72 polymorphism in our population. Also, the distribution of tumor size, lymph node involvement and tumor grade was not significantly different among the polymorphic variants. CONCLUSION: We conclude that p53 codon72 polymorphism is involved in susceptibility to developing breast cancer. It may be a factor of progression when breast sites are taken into account. However, there is no evidence indicating that Arg72Pro SNP may influence response to anthracycline-based chemotherapy.